Cryptic Diversity, Molecular Systematics, and Pathogenicity of GenusPestalotiopsisand Allied Genera Causing Gray Blight Disease of Tea in Taiwan, With a Description of a NewPseudopestalotiopsisSpecies

Abstract

Camellia sinensis (L.) O. Kuntze, commonly known as tea, is widely cultivated around the world in tropical and subtropical areas. Tea is mainly manufactured using young shoots of tea plants. Therefore, it is essential to control foliar diseases. Grey blight disease is caused by Pestalotiopsis-like taxa and is known as one of the most destructive tea diseases. Although several studies have provided the groundwork for the fungal diseases associated with C. sinensis in Taiwan, grey blight disease has not been characterised based on diversity, molecular systematics, or pathogenicity. The goal of this study was to identify and characterise the causative agents of tea grey blight disease. A total of 98 Pestalotiopsis-like isolates associated with symptomatic leaves of C. sinensis from major tea fields in Taiwan were investigated. Based on phylogenies of single and concatenated DNA sequences (ITS, tub2, tef1-α) together with morphology, we resolved most of the Pestalotiopsis-like species in this study. The study revealed seven well-classified taxa and seven tentative clades in three genera, i.e., Pestalotiopsis, Pseudopestalotiopsis, and Neopestalotiopsis. One novel species, Ps. annellata, was introduced. Five new records – Ps. chinensis, Ps. camelliae-sinensis, P. camelliae, P. yanglingensis and P. trachicarpicola – were introduced for the first time in Taiwan. Ps. chinensis was the taxon most frequently isolated from C. sinensis in this study. Further, results of pathogenicity assessments exhibited that, with wound inoculation, all assayed isolates in this study were pathogenic on tea leaves. Ps. chinensis and Ps. camelliae-sinensis were identified as the major pathogens associated with grey blight disease of tea in Taiwan. This is the first study of the diversity, pathogenicity and characterisation of Pestalotiopsis-like fungi associated with tea grey blight disease in Taiwan.

Molecular Phylogenetic Diversity and Biological Characterization of Diaporthe Species Associated with Leaf Spots of Camellia sinensis in Taiwan

“…Foliar fungal pathogens that infect Camellia sinensis can lead to a notable reduction in their yield, resulting in a loss of income [ 3 , 32 , 33 ]. Tea leaves at all stages are susceptible to fungal diseases [ 3 , 32 , 33 ].…”

“…Foliar fungal pathogens that infect Camellia sinensis can lead to a notable reduction in their yield, resulting in a loss of income [ 3 , 32 , 33 ]. Tea leaves at all stages are susceptible to fungal diseases [ 3 , 32 , 33 ]. In total, 520 fungal species have been identified to occur on Camellia species, of which 303 were reported from C. sinensis according to the U.S. Department of Agriculture (USDA) database [ 3 , 4 ].…”

“…In total, 520 fungal species have been identified to occur on Camellia species, of which 303 were reported from C. sinensis according to the U.S. Department of Agriculture (USDA) database [ 3 , 4 ]. Various fungi are known to cause diseases of leaves, stems, and roots of C. sinensis and other Camellia species, for example, brown blight caused by Colletotrichum species, gray blight by Pestalotiopsis -like taxa, leaf spots and dieback by Diaporthe species, and blister blight by Exobasidium vexans [ 3 , 32 , 33 ]. Our research group studies various foliar diseases allied with tea farms in Taiwan [ 32 , 33 ].…”

“…Various fungi are known to cause diseases of leaves, stems, and roots of C. sinensis and other Camellia species, for example, brown blight caused by Colletotrichum species, gray blight by Pestalotiopsis -like taxa, leaf spots and dieback by Diaporthe species, and blister blight by Exobasidium vexans [ 3 , 32 , 33 ]. Our research group studies various foliar diseases allied with tea farms in Taiwan [ 32 , 33 ]. Our previous work has indicated that in addition to the major fungal diseases, such as brown blight due to Colletotrichum species complex and grey blight disease caused by Pestalotiopsis -like taxa, numerous other fungal species can potentially cause leaf spots on C. sinensis in Taiwan [ 32 , 33 ].…”

“…Our research group studies various foliar diseases allied with tea farms in Taiwan [ 32 , 33 ]. Our previous work has indicated that in addition to the major fungal diseases, such as brown blight due to Colletotrichum species complex and grey blight disease caused by Pestalotiopsis -like taxa, numerous other fungal species can potentially cause leaf spots on C. sinensis in Taiwan [ 32 , 33 ]. Therefore, the aim of this study was to fully characterize the diversity and phylogeny of Diaporthe -like strains originally isolated from the leaf spots of C. sinensis and evaluate their pathogenicity to the major tea cultivar Chin-Shin Oolong grown in Taiwan’s tea fields.…”